The present invention relates to an apparatus for placing and deploying supple surgical materials such as surgical mesh within the body, and more particularly to a substantially planar surgical mesh prosthesis for bridging a hernia and an apparatus for placing and deploying the prosthesis.
Modern surgical techniques are intended to be minimally invasive. Endoscopic surgery is a prime example of this minimally invasive approach and has led to the development of various instruments that may be inserted through a small incision to operate internally. In some circumstances, such as with specimen retrieval pouches or organ pouches and bags, the surgical instrument places, controls and/or deploys a supple material, e.g., a latex bag. The supple material may assume folded, expanded and contracted states, e.g., for inserting, opening and closing within the body. Accordingly, various apparatus have been devised to accomplish these transitions and functions relative to supple surgical materials like latex sheeting and textiles, but these apparatus are frequently complex, expensive and utilize exotic materials.
Minimally invasive procedures are also commonly employed in the treatment of hernias, e.g., in the placement of mesh surgical prostheses. Surgically implantable mesh patches for the repair of inguinal and other abdominal wall hernias are commonly used and provide tension-free repairs by bridging the hernia defect. Patches of this type constitute a structural support which decreases recurrence rates and because they do not require the displacement of tissues to cover the hernia, decrease postoperative discomfort. Frequently, prostheses of this type are sutured in place, i.e., proximate to the periphery of the patch. An alternative to suturing the prosthesis is to insert it into the properitoneal space. U.S. Pat. No. 5,916,225 to Kugel discloses a hernia prosthesis having a resilient ring made of synthetic material, such as nylon, polypropylene or polyester enclosed within a pocket formed by opposing planar segments of surgical mesh that are attached together to encapsulate the ring. A slit is provided in one of the planar segments to permit the surgeon to insert a finger therein in order to push the prosthesis through an incision in the abdominal wall into the properitoneal space and across the hernia. The resilient ring urges the pocket into a deployed planar configuration, i.e., to straighten the wrinkling and folding of the pocket that occurs in the course of its placement. The disadvantages associated with the device disclosed in U.S. Pat. No. 5,916,225 are that each layer of mesh is stiff and dense, such that the combination of two layers and the resilient ring constitutes a rigid, high mass prosthesis which tends to cause discomfort and resists conformance to the patient""s anatomy. Further, the high mass prosthesis with resilient ring must be compressed into a stressed condition in order to be passed through the incision. Alternatively, the incision must be made large enough to pass the fully expanded prosthesis.
It is therefore an object of the present invention to provide a hernia repair prosthesis for use in a surgical hernia repair that has low mass, greater flexibility and that may be placed proximate to the site of the defect through a small incision in a stress free condition. More generally, it remains an objective to devise simple effective apparatus for positioning, deploying and controlling supple surgical material, such as a surgical mesh hernia prosthesis.
The problems and disadvantages associated with conventional supple surgical material deployment devices are overcome by the present invention which includes an elongated rod having a proximal end and a distal end. A drawstring with a first end and a second end runs along the length of the rod from the proximal end to the distal end and slidably passes through an opening at the distal end of the rod. The drawstring forms a loop at the distal end of the rod and the loop has a variable circumference varying between an expanded circumference and a reduced circumference, depending upon the position of said first end relative to said rod. A plurality of segments, each having a lumen therethrough, is threaded over the drawstring in the area of the loop. The segments bear against one another when the circumference of the loop is reduced and assume a relative alignment such that they are arranged to approximate a generally planar closed figure.